Detergent



so since ordinary soap is Patented July 7, 1931 ump. nown, or cnr'caeo, rumors,

.nssreivon rro ran ALDEN srnnnn's sons CO, BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS nze'rnaennr 80 Drawing.

ents of the My invention relates to deter in general class employed in laundries, an

has these objects:

(1.) To provide simple means for overcoming the hygroscopic characteristics of certain detergents, so that such detergents can readily be stored and shipped without caking, and also can readily be measured out and used in finely divided form.

(2) To provide a simple method for combining a hygroscopic detergent with a cake-,

' preventing detergent.

(3) To provide novel, inexpensive and etficient detergent compositions suitable for laundry-use. v I I.

In commercial laundries it has long been recognized that soap alone is not adequate for the speedy. cleansing of goods and for the proper whitening of linens and the like, slow to loosen the dirt, although the soap is highly effective for lubricating and carrying off the detached dirt and the like. Consequently, sodium carbonate (known in the trade as sodaoash or-washingsoda) is commonly employed along with the soap, but this tends to weaken the clothes and to turn white goods gray. To offset the excess of alkalinity of the sodium carbonate or the like, it is advisable to employ another detergent ingredient also, and preferably one which will also soften'the water and whiten linens 'or the like.

While numerous materials may be eming, the cost makes many such materials rohibitive, while others have been barred rom such use sco ic nature makes it impractical to ship an handle them in finely divided form. For example, a silicate of the general character of a sodium metasilicate, would be highly desirable as a combined water softener, whitener and antidote to excessive alkalinity, in view of its low cost. However, the commercial sodium metasilicate (which is available on the market with a content of about 27 percent sodium oxide, 26 percent silica and i7 percent water) is so hygroscopic that exposure to the air ployed for. this water-softening and whitenbecause their highly hygro-' Application filed occoterao, 192v: Serial No. 227,626.

quickly causes it to cake by having the particles knit together. If finely ground and shipped or stored in barrels, it soon cakes or knits into a solid mass of such hardness as to require an axe to chip it out, and the resulting chunks soften slowly when moistened. Consequently, the commercial sodium metasilicate when it reaches the laundries -cannot readily be measured out in the desired quantity (as needed in proportion to the soap and the soda ash or other alkali),cannot be spread in dry powdered form on the socalled wheel of a commerical washin machine, and cannot be easily and quic y employed in household washing machines.

This is true of the numerous metasilicates of; soda, for each of which the formula is Na SiOgfollowed by the number of molecules of water by whichvthe particular metasilicate is distinguished. Thus, the commercial tetrahydrated sodium metasilicate has the formula Na SiO plus ell-I 0, while the pentahydrated and hexahydrated forms respectively have five and s1x molecules of water in place of the four in the tetrahydrated form. q f

In one of its impm'tant ob'ects, my invention provides a simple and inexpensive method for treating sodium metasilicate or the like so as to render it non-caking, there by enabling it to be stored, shipped and measured out in finely divided form. Furthermore, my invention effects this treatment by employing another ingredient which is itself a detergent, namely soap,

and provides a novel product in which the cake-preventing soap is so intimately combined with the metasilicate that the resulting action on the clothes is more speedy and effective than when the same ingredients areseparately introduced intothe washing solution. V

Furthermore, my invention provides finely divided forms of detergent compositions in which suitably proportioned quantities of a suitable metasilicate, asoap and an alkali are all combined in a powder which 'dissolve almost instantly and which can be powder.

stored indefinitely under ordinary atmospheric conditions without caking.

To make such a metasilicate non-.caking, I intimately work it up with at least sufficient soap for sealing the exterior pores of the particles of metasilicate and coating these particles-with a film of soap. This I can readily do by initially grinding the metasilicate to a larger grained powder than that desired for the final product, then mixing it with the soap and regrinding the mixture. The resulting composition is a powder, dry to the touch, and which remains so dry under ordinary storage and shipping conditions that it can readily be sprinkled or otherwise distributed, as a When used in a washing machine, it dissolves almost instantly and acts with unusual speed both for whitening linens and for removing the dirt. I have not as yet ascertained the cause of thisgreater rapidity of action, but it may be this: that the im-,

pregnating of each particle of the metasilicate in a film of soap causes each dissolved particle to be (at least partially) housed by a film of dissolved soap, which film is then disposed in such intimate association with the dissolved metasilicate that is instantly acts as a carrier for the dirt de tached by the action ofithe' metasilicate.

When an additional ingredient, such as soda ash or other alkali, is also desired in the same composition, I intermix this with the metasilicate either before or after adding the soap, and in practice ma metasilicate and soda ash toget er initially,

and then regrind them after adding the,

soap. However, I preferably reduce the needed amount of soap by first soap-coating the metasilicate and then mixing these coated particleswith the soda ash or other ingredient or ingredients. In practice, I preferably em 10y a neutral soap, and the proportion 0 this. to the metasilicate will obviously vary somewhat with the nature of the soap and with the watercontent of the metasilicate.

Illustrative of such a non-caking detergent composition with three ingredients, I

have secured good results by using these proportions: 30 pounds sodium metasilicate, 10

pounds neutral soap, and pounds soda ash Since the soap in this formula repre-' sents only a tenth of the total weight, and since .the other two ingredients are both much cheaper per pound than soap, the cost of such a three-ingredient detergent composition per pound may be less than one third of the soa in it. Likewise, the cost per pound of t e metasilicate adequately sealed against caking by soap can easilybe less than half that of the soap. Conse-- quently, I can readily provide highly effective Washing compounds at a low cost,

grind the in addition to facilitating their shipping, storing and handling. v

However, while I have described two novel products both including metasilicate of soda as one ingredient, and one of which includes sodium carbonate also, I do not wish to be limited to these articular ingredients, since the pore-sealing and filmcoating action of the soa would obviously be the same with other hygroscopic detergents (such as potassium metasilicate), and since one or more other ingredients could readily be substituted for the sodium carbonate.

Neither do I wish to be limited to the pregrinding of the hygroscopic detergent before treating it with the soap, since my novel product can also be produced by a other ingredients-conjointly with its application to the hygroscopic ingredient,

since part of the soap would then impregnate and adhere to these other ingredients.

Nor do I wish to be limited to the pro- 'viding of my novel products in powdered forms, or to a grinding procedure. For example, if sodium metasilicate intended for laundry uses is to be stored or shipped in lumps, these lumps may be surface-treated by working them up with soap, thereby preventing them from knitting together and e'nce permitting the separate lumps to be withdrawn from thebarrels or other containers later on.

Furthermore, I am using the term sodium metasilicate in the appended claims in the broad sense in which this includes both the anhydrous form (Na SiOs) and the numerous hydrates which have specific chemical designations according to the number of moleculesof water associated with the Na .SiO All of these are hygroscopic so that they cannot readily be shipped or stored commercially in owdered form unless prefilmed with soap after the manner here disclosed.

So also, it is to be understood that my invention has no reference to the ordinary sodium silicate or socalled water-glass which is frequently used as a filler or adulterant to add weight to soaps or soa ders. This common sodium silicate which has a much higher content of silica in proportion to the sodium) dissolves only slowly and to a jelly-like or colloidal solution which powwill not mix freely with the suds and which cannot readily'be rinsed out of the goods afterwards, whereas both sodium metasilicate and the mixtures of it to which my invention relates dissolve readily into solutions which freely intermingle with the suds, which produce a whitening efiect not attained by the sodium silicate, and which are readily rinsed out of the goods. In other words, myinvention enables laundrymen to profit by the high detergent qualities of the sod'um metasilicate which heretofore could not be employed commercially because of its cakin I c aim as my invention: 1. The method of preventing the cakini of a comminuted sodium metasilicate whic consists in intimately intermingling this with approximately one third its own weight of soap.

2.1The non-caking powder comprising granulated sodium metasilicate with about one-third of its weight of soap. I p

3. A non-caking etergent powder readily soluble in water, comprising granulated sodium meta'silicatewith about onethirdits weight of neutral soap and twice its weight of soda ash.

Signed at Chicago, Illinois, October 18th,

WILLIAM G. HOWE. 

